Many of our attitudes about food and eating are developed during childhood. Thus, the health and nutritional condition of the child, and of the subsequent adult, are shaped by childhood feeding experiences. However, our understanding of how food preferences, eating habits and skills are learned is still very rudimentary. We do know that human infants rely, to a much greater extent than perhaps any other mammal, on social means to acquire food-related information. The marmosets and tamarins are unique among non-human primates in the degree to which family members provision weaned young, much as we humans provision our young. This study proposes to use the golden lion tamarin as a model for the study of the development of food selection and eating habits in humans. It will focus on the interplay between independent trial and error learning and social learning about food during the tamarins' first year of life. Field observations and collection for nutritional analysis of food types given to immature tamarins by older group members will be used to examine the functions of provisioning, to describe the various means by which young acquire food and how these food acquisition strategies change during ontogeny, and to describe the roles of caretakers in determining food intake by the young. Behavioral experiments designed to measure the effects of food familiarity on food transfer interactions will be conducted on captive family groups to further examine the functions of provisioning. Playback experiments of infant begging calls also will be conducted on groups in captivity in order to more clearly assess the costs of begging for food by the young. Thus, natural variation in the behavior of wild animals and controlled experimental variation will be used to test hypotheses regarding the development of food selection and foraging skills.